You feel it. If not, learn feeling your real body needs. It is important if you want to take best care of the machine.

dydde wrote:

Raw fooders etc say that 8-12 times a day you should pee and it should be crystal clear then you are hydrated.

That looks like a fanatism
No, because the kidneys are not a toilet that you flush with water. Feel what the body needs in terms of drinking and be aware, that every body is different. Amount of water needed by body depends on a dozen of different circumstances, for example: climate, physical activity, feed consumed, duration of sleep, clothing, expose to Sun.